ruby的字符串處理函數

1.返回字符串的長度

str.length => integer

2.判斷字符串中是否包含另外一個串

str.include? other_str => true or false

"hello".include? "lo"   #=> true

"hello".include? "ol"   #=> false

"hello".include? ?h     #=> true

3.字符串插入:

str.insert(index, other_str) => str

"abcd".insert(0, 'X')    #=> "Xabcd"

"abcd".insert(3, 'X')    #=> "abcXd"

"abcd".insert(4, 'X')    #=> "abcdX"

"abcd".insert(-3, 'X')

-3, 'X')   #=> "abXcd"

"abcd".insert(-1, 'X')   #=> "abcdX"

4.字符串分隔,默認分隔符爲空格

str.split(pattern=$;, [limit]) => anArray

" now's  the time".split        #=> ["now's", "the", "time"]

"1, 2.34,56, 7".split(%r{,\s*}) #=> ["1", "2.34", "56", "7"]

"hello".split(//)               #=> ["h", "e", "l", "l", "o"]

"hello".split(//, 3)            #=> ["h", "e", "llo"]

"hi mom".split(%r{\s*})         #=> ["h", "i", "m", "o", "m"]

"mellow yellow".split("ello")   #=> ["m", "w y", "w"]

"1,2,,3,4,,".split(',')         #=> ["1", "2", "", "3", "4"]

"1,2,,3,4,,".split(',', 4)      #=> ["1", "2", "", "3,4,,"]

5.字符串替換

str.gsub(pattern, replacement) => new_str

str.gsub(pattern) {|match| block } => new_str

"hello".gsub(/[aeiou]/, '*')              #=> "h*ll*"     #將元音替換成*號

"hello".gsub(/([aeiou])/, '<\1>')         #=> "hll"   #將元音加上尖括號,\1表示保留原有字符???

"hello".gsub(/./) {|s| s[0].to_s + ' '}   #=> "104 101 108 108 111 "

字符串替換二:

str.replace(other_str) => str

s = "hello"         #=> "hello"

s.replace "world"   #=> "world"

6.字符串刪除:

str.delete([other_str]+) => new_str

"hello".delete "l","lo"        #=> "heo"

"hello".delete "lo"            #=> "he"

"hello".delete "aeiou", "^e"   #=> "hell"

"hello".delete "ej-m"          #=> "ho"

7.去掉前和後的空格

str.lstrip => new_str

"  hello  ".lstrip   #=> "hello  "

"hello".lstrip       #=> "hello"

8.字符串匹配

str.match(pattern) => matchdata or nil

9.字符串反轉

str.reverse => new_str

"stressed".reverse   #=> "desserts"

10.去掉重複的字符

str.squeeze([other_str]*) => new_str

"yellow moon".squeeze                  #=> "yelow mon"  #默認去掉串中全部重複的字符

"  now   is  the".squeeze(" ")         #=> " now is the"  #去掉串中重複的空格

"putters shoot balls".squeeze("m-z")   #=> "puters shot balls"  #去掉指定範圍內的重複字符

11.轉化成數字

str.to_i=> str

"12345".to_i             #=> 12345

chomp和chop的區別:

chomp:去掉字符串末尾的\n或\r

chop:去掉字符串末尾的最後一個字符,不論是\n\r仍是普通字符

"hello".chomp            #=> "hello"

"hello\n".chomp          #=> "hello"

"hello\r\n".chomp        #=> "hello"

"hello\n\r".chomp        #=> "hello\n"

"hello\r".chomp          #=> "hello"

"hello".chomp("llo")     #=> "he"

"string\r\n".chop   #=> "string"

"string\n\r".chop   #=> "string\n"

"string\n".chop     #=> "string"

"string".chop       #=> "strin"